L3 switchiong is just term for idiots - it is ROUTING in old terms. So, VLAN's means _routing_. The point of using VLAN's is that, in many cases, IP routing for VLANs is provided by the switching fabric, very effectively. And that you have universal patching - everything is very flexible. But .. managing 100 Cisco 3550 (or other venor, no matter) switches wiith 4,000 VLAN's... brr, it is a very seriuos task. I'd think about central 6509 switch(es), with a few local (in rack) dumb 3524 switches to decrease a patching... or about private VLAN (single!) . If they mean dynamic VLAN's so that they assign VLAN to the MAC, they expect to assign 4,000 different VLAN's. Having 4,000 LVALs means that workstations are just isolated. Ok, set up 1 (one) private VLAN, and workstations are isolated (be very careful, because it will require careful ARP configuration, careful proxy arp etc etc... but it is possible. Or just keep 1 VLAN and many ssecondary IP per interface... I think, that you can find many options.). May be (I can not exclude it), they have a very good idea, which pay off when configured. As I was saying, I can not exlude it, and I am sure, that it is possible to find non-cisco L3 switches, able to do such task much better than Cisco. The only drawback is _time te test it all_ and _time to select such vendor_. ----- Original Message ----- From: "ken emery" <ken@cnet.com> To: <nanog@merit.edu> Sent: Sunday, January 25, 2004 5:18 PM Subject: Re: Any 1U - 2U Ethernet switches that can handle 4K VLANs?
On Sun, 25 Jan 2004, Bill Nash wrote:
On Sun, 25 Jan 2004, ken emery wrote:
The point of using VLANs is that you don't need to route. There's probably a good reason for switching instead of routing in the
original
poster's scenario. (Perhaps a FTTH-like project?)
Correct me if I'm wrong here, but at some point you will have to route all those VLAN's. To really answer the question about wether > 1000 VLAN's are necessary one would need to see the network design.
I would argue this point. I've got a production environment sporting multiple vlans, none which will ever see an external subnet or even a gateway (think databases.) The operative context inherent in the VLAN acronym is, after all, 'local', and not every topology requires routing.
This is correct, but then why spend the money on a L3 switch? Routing isn't needed so save the money and purchase a L2 switch.
bye, ken emery